A ferroelectric thin film or thick film is frequently used in various electric and electronic parts, and it has been hitherto prepared by coating a PZT film on a substrate by a screen-printing or sol-gel method, calcining the coated substrate to crystallize the material, or by depositing the single crystal-forming raw material under a vacuum (see N. Setter, Piezoelectric Materials in Devices, Ceramics Laboratory, EPFL 2002).
Although the prior methods are simple and convenient, the film thus prepared still exhibits unsatisfactory performance characteristics in terms of current loss, electromechanical coupling coefficient and dielectric constant. Further, the calcination step of the prior methods requires the use of a high-cost, high-melting metal such as Pt and Au as an electrode material.
Therefore, there has existed a need to develop a simple method of providing a ferroelectric film, especially in the form, of a single crystal layer, of improved properties suitable for electric and electronic devices and parts.